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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 1,441 records · Page 80
All sourcesNASA NTRSDOE OSTI
DOE OSTI2015

Atomic arrangement at ZnTe/CdSe interfaces determined by high resolution scanning transmission electron microscopy and atom probe tomography

High resolution scanning transmission electron microscopy and atom probe tomography experiments reveal the presence of an intermediate layer at the interface between two binary compounds with no common atom, namely, ZnTe and CdSe for samples grown by Molecular Beam Epitaxy under standard conditions. This thin transition layer, of the order of 1 to 3 atomic planes, contains typically one monolayer of ZnSe. Even if it occurs at each interface, the direct interface, i.e., ZnTe on CdSe, is sharper than the reverse one, where the ZnSe layer is likely surrounded by alloyed layers. On the other hand, a CdTe-like interface was never observed. This interface knowledge is crucial to properly design superlattices for optoelectronic applications and to master band-gap engineering.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2020

Mycobacterium Phage Butters-Encoded Proteins Contribute to Host Defense against Viral Attack [plus supplemental information]

A diverse set of prophage-mediated mechanisms protecting bacterial hosts from infection has been recently uncovered within cluster N mycobacteriophages isolated on the host, Mycobacterium smegmatis mc 2 155. In that context, we unveil a novel defense mechanism in cluster N prophage Butters. By using bioinformatics analyses, phage plating efficiency experiments, microscopy, and immunoprecipitation assays, we show that Butters genes located in the central region of the genome play a key role in the defense against heterotypic viral attack. Our study suggests that a two-component system, articulated by interactions between protein products of genes 30 and 31, confers defense against heterotypic phage infection by PurpleHaze (cluster A/subcluster A3) or Alma (cluster A/subcluster A9) but is insufficient to confer defense against attack by the heterotypic phage Island3 (cluster I/subcluster I1). Therefore, based on heterotypic phage plating efficiencies on the Butters lysogen, additional prophage genes required for defense are implicated and further show specificity of prophage-encoded defense systems. IMPORTANCE: Many sequenced bacterial genomes, including those of pathogenic bacteria, contain prophages. Some prophages encode defense systems that protect their bacterial host against heterotypic viral attack. Understanding the mechanisms undergirding these defense systems is crucial to appreciate the scope of bacterial immunity against viral infections and will be critical for better implementation of phage therapy that would require evasion of these defenses. Furthermore, such knowledge of prophage-encoded defense mechanisms may be useful for developing novel genetic tools for engineering phage-resistant bacteria of industrial importance.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2018

On Principles, Values, Metrics and Criteria for the Development of Magnetic Fusion Energy

Fusion energy holds the promise of providing abundant, safe, clean and environmentally sustainable power for the foreseeable future. Hence, fusion has enormous potential to benefit society if it can be developed into a commercial energy source in a timely manner. However, the task of developing fusion energy is a challenging endeavor and it is believed that it will take several decades in order to reach the final goal. Hence, it is imperative to develop a strategic plan and to periodically revise and update this plan. In 2017, the Department of Energy (DOE) Office of Fusion Energy Sciences (FES) commissioned the National Academy of Sciences (NAS) to provide a long term strategic plan for magnetic fusion energy (MFE). In turn, the MFE community mobilized to provide input to the NAS panel. This resulted in a series of US Magnetic Fusion Energy Research Strategic Directions (US MFRSD) Workshops.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2022

NCSP Training and Education Program [Slides]

The mission of the Nuclear Criticality Safety Program is to provide sustainable expert leadership, direction and the technical infrastructure necessary to develop, maintain, and disseminate the essential technical tools, training, and data required to support safe, efficient fissionable material operations within DOE; the vision of the program is a Continually improving, adaptable, and transparent program that communicates and collaborates globally to incorporate technology, practices, and programs to be responsive to the essential technical needs of those responsible for developing, implementing, and maintaining nuclear criticality safety. Training and education topics for the program include a 1-week Manager/Criticality Safety Officer Course and a 2-week NCS Engineer Hands-on Training Course.

42 ENGINEERING↗
DOE OSTI2022

Hypothesis testing via AI: Generating physically interpretable models of scientific data with machine learning (Full Technical Report)

Deep learning has demonstrated an exceptional ability to solve complex tasks (an engineering success); however, it has done so at the expense of the ability to generate new knowledge (a scientific failure). We propose an alternative framework—entitled Deep Symbolic Regression (DSR)—in which artificial neural networks (NNs) rapidly generate hypotheses about physical relationships among inputs. This framework bypasses the need to interpret an NN altogether, while still leveraging the representational power of deep learning. The resulting models are tractable mathematical expressions, which are inherently and readily human interpretable and can provide insights into underlying physical phenomena. Further, we fold this methodology into the scientific process by allowing the scientist to directly integrate a priori knowledge and beliefs to accelerate learning. We demonstrate this methodology on symbolic regression—the problem of rediscovering underlying expressions describing a dataset—and achieve state-of-the-art performance across a wide variety of symbolic regression problems. Further, we generalize our DSR framework to apply to the more general class of symbolic optimization problems, in which one seeks to optimize a sequence of symbols or “tokens” under a black-box reward function. Examples of other symbolic optimization problems include neural architecture search and computational antibody design. Our generalized tool, Deep Symbolic Optimization (DSO), has been demonstrated on the task of learning symbolic control policies for reinforcement learning environments, and has been adopted as an enabling capability for computational antibody design.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2023

Professional Development for Technical Managers [Slides] (Rev. 1)

LANL is changing rapidly and requires a leadership development program in order to support the growing and changing workforce. Provide analysis and recommendations for a leadership development program for engineering services within ALDFO: 1) Attrition and churn are up; 2) Younger workforce--loss of organizational knowledge; 3) LANL is geographically isolated; 4) Leadership training is infrequent and one-size-fits-all.

96 KNOWLEDGE MANAGEMENT AND PRESERVATION↗
NASA NTRS1962

Post-buckling behavior of cylindrical shells. part iii. torsion

This is a continuation of two monographs bearing the same general title already published by the author under the auspices of the Publishing House of Khar'kov University. It deals with the elastic post-buckling behavior of a cylindrical shell stressed in torsion. In particular, the critical loads are determined. Generally speaking, the exposition is on an elementary level and intended for a wide circle of readers with a knowledge of the elements of shell theory and differential geometry. It will prove useful to design engineers, mechanical engineering students, and scientists interested in the theory of shells.

BUCKLING↗
NASA NTRS1977

Biomedical Results from Skylab

Through the years, the quest for more knowledge about space and its impact on man sparked the technological advances in related scientific and engineering disciplines. Happily, at this present point in human history, sufficiently advanced technology and man's will to explore the unknown joined forces to make space flight possible. Following this breakthrough, the further understanding of the nature and extent of man's capabilities in space became an urgent issue. Inquiries about how man might behave, prosper, or be adversely affected in the unique environment accompanying space exploration have influenced the course of the space flight program. This book chronicles the work of scientists attempting to understand the responses of man and his life processes in an environment previously totally unknown to living systems.

Richard S Johnston↗
NASA NTRS1988

Computer sciences

The Computer Science Program provides advanced concepts, techniques, system architectures, algorithms, and software for both space and aeronautics information sciences and computer systems. The overall goal is to provide the technical foundation within NASA for the advancement of computing technology in aerospace applications. The research program is improving the state of knowledge of fundamental aerospace computing principles and advancing computing technology in space applications such as software engineering and information extraction from data collected by scientific instruments in space. The program includes the development of special algorithms and techniques to exploit the computing power provided by high performance parallel processors and special purpose architectures. Research is being conducted in the fundamentals of data base logic and improvement techniques for producing reliable computing systems.

Smith, Paul H.↗
NASA NTRS1998

Model Based Autonomy for Robust Mars Operations

Space missions have historically relied upon a large ground staff, numbering in the hundreds for complex missions, to maintain routine operations. When an anomaly occurs, this small army of engineers attempts to identify and work around the problem. A piloted Mars mission, with its multiyear duration, cost pressures, half-hour communication delays and two-week blackouts cannot be closely controlled by a battalion of engineers on Earth. Flight crew involvement in routine system operations must also be minimized to maximize science return. It also may be unrealistic to require the crew have the expertise in each mission subsystem needed to diagnose a system failure and effect a timely repair, as engineers did for Apollo 13. Enter model-based autonomy, which allows complex systems to autonomously maintain operation despite failures or anomalous conditions, contributing to safe, robust, and minimally supervised operation of spacecraft, life support, In Situ Resource Utilization (ISRU) and power systems. Autonomous reasoning is central to the approach. A reasoning algorithm uses a logical or mathematical model of a system to infer how to operate the system, diagnose failures and generate appropriate behavior to repair or reconfigure the system in response. The 'plug and play' nature of the models enables low cost development of autonomy for multiple platforms. Declarative, reusable models capture relevant aspects of the behavior of simple devices (e.g. valves or thrusters). Reasoning algorithms combine device models to create a model of the system-wide interactions and behavior of a complex, unique artifact such as a spacecraft. Rather than requiring engineers to all possible interactions and failures at design time or perform analysis during the mission, the reasoning engine generates the appropriate response to the current situation, taking into account its system-wide knowledge, the current state, and even sensor failures or unexpected behavior.

Kurien, James A.↗
NASA NTRS2010

NASA Tech Briefs, October 2010

Topics covered include: Hybrid Architecture Active Wavefront Sensing and Control; Carbon-Nanotube-Based Chemical Gas Sensor; Aerogel-Positronium Technology for the Detection of Small Quantities of Organic and/or Toxic Materials; Graphene-Based Reversible Nano-Switch/Sensor Schottky Diode; Inductive Non-Contact Position Sensor; High-Temperature Surface-Acoustic-Wave Transducer; Grid-Sphere Electrodes for Contact with Ionospheric Plasma; Enabling IP Header Compression in COTS Routers via Frame Relay on a Simplex Link; Ka-Band SiGe Receiver Front-End MMIC for Transponder Applications; Robust Optimization Design Algorithm for High-Frequency TWTs; Optimal and Local Connectivity Between Neuron and Synapse Array in the Quantum Dot/Silicon Brain; Method and Circuit for In-Situ Health Monitoring of Solar Cells in Space; BGen: A UML Behavior Network Generator Tool; Platform for Post-Processing Waveform-Based NDE; Electrochemical Hydrogen Peroxide Generator; Fabrication of Single, Vertically Aligned Carbon Nanotubes in 3D Nanoscale Architectures; Process to Create High-Fidelity Lunar Dust Simulants; Lithium-Ion Electrolytes Containing Phosphorous-Based, Flame-Retardant Additives; InGaP Heterojunction Barrier Solar Cells; Straight-Pore Microfilter with Efficient Regeneration; Determining Shear Stress Distribution in a Laminate; Self-Adjusting Liquid Injectors for Combustors; Handling Qualities Prediction of an F-16XL-Based Reduced Sonic Boom Aircraft; Tele-Robotic ATHLETE Controller for Kinematics - TRACK; Three-Wheel Brush-Wheel Sampler; Heterodyne Interferometer Angle Metrology; Aligning Astronomical Telescopes via Identification of Stars; Generation of Optical Combs in a WGM Resonator from a Bichromatic Pump; Large-Format AlGaN PIN Photodiode Arrays for UV Images; Fiber-Coupled Planar Light-Wave Circuit for Seed Laser Control in High Spectral Resolution Lidar Systems; On Calculating the Zero-Gravity Surface Figure of a Mirror; Optical Modification of Casimir Forces for Improved Function of Micro- and Nano-Scale Devices; Analysis, Simulation, and Verification of Knowledge-Based, Rule-Based, and Expert Systems; Core and Off-Core Processes in Systems Engineering; Digital Reconstruction Supporting Investigation of Mishaps; and Template Matching Approach to Signal Prediction.

Source record↗
NASA NTRS2011

Advanced X-Ray Timing Array (AXTAR) Animation

The animation depicts NASA's concept for a next-generation Advanced X-ray Timing Mission. The models and their textures doe not necessarily represent the final iteration. Delivery specifications include launch with Taurus II or Falcon 9, mass of 2650 kg, with a circular low earth orbit at approximately 600 km. The inclination depends on the launch vehicle and spacecraft mass. AXTAR's prime instrument will probe the physics of neutron stars and black holes through X-ray timing and spectral measurements. The primary instrument will be the Large Area Timing Array (LATA). The Sky Monitor Clusters configuration consists of 27 Sky Monitor cameras th at are grouped in five clusters. This configuration will achieve approximately 85 percent all sky coverage. Spacecraft components include a science bus to house the LATA of supermodules; a spacecraft bus to house components such as propulsion tanks, avionics, and reaction wheels; solar arrays configured from space-qualified GaAs 3-junction cells; star trackers for attitude knowledge; a propulsion system of four pods, each containing one 100 lbf and two 5 lbf engines; a launch vehicle adaptor; and a radiation shield.

Hopkins, Randall C.↗
NASA NTRS2016

A Geology Sampling System for Microgravity Bodies

Human exploration of microgravity bodies is being investigated as a precursor to a Mars surface mission. Asteroids, comets, dwarf planets, and the moons of Mars all fall into this microgravity category and some are been discussed as potential mission targets. Obtaining geological samples for return to Earth will be a major objective for any mission to a microgravity body. Currently the knowledge base for geology sampling in microgravity is in its infancy. Humans interacting with non-engineered surfaces in microgravity environment pose unique challenges. In preparation for such missions a team at the NASA Johnson Space Center has been working to gain experience on how to safely obtain numerous sample types in such an environment. This paper describes the type of samples the science community is interested in, highlights notable prototype work, and discusses an integrated geology sampling solution.

Hood, Anthony↗
NASA NTRS2016

A Geology Sampling System for Small Bodies

Human exploration of microgravity bodies is being investigated as a precursor to a Mars surface mission. Asteroids, comets, dwarf planets, and the moons of Mars all fall into this microgravity category and some are being discussed as potential mission targets. Obtaining geological samples for return to Earth will be a major objective for any mission to a small body. Currently, the knowledge base for geology sampling in microgravity is in its infancy. Humans interacting with non-engineered surfaces in microgravity environment pose unique challenges. In preparation for such missions a team at the NASA Johnson Space Center has been working to gain experience on how to safely obtain numerous sample types in such an environment. This paper describes the type of samples the science community is interested in, highlights notable prototype work, and discusses an integrated geology sampling solution.

Naids, Adam J.↗
NASA NTRS2016

Misconceptions of Synthetic Biology: Lessons from an Interdisciplinary Summer School

In 2014, an international group of scholars from various fields analysed the "societal dimensions" of synthetic biology in an interdisciplinary summer school. Here, we report and discuss the biologists' observations on the general perception of synthetic biology by non-biologists who took part in this event. Most attendees mainly associated synthetic biology with contributions from the best-known public figures of the field, rarely mentioning other scientists. Media extrapolations of those contributions appeared to have created unrealistic expectations and irrelevant fears that were widely disconnected from the current research in synthetic biology. Another observation was that when debating developments in synthetic biology, semantics strongly mattered: depending on the terms used to present an application of synthetic biology, attendees reacted in radically different ways. For example, using the term "GMOs" (genetically modified organisms) rather than the term "genetic engineering" led to very different reactions. Stimulating debates also happened with participants having unanticipated points of view, for instance biocentrist ethicists who argued that engineered microbes should not be used for human purposes. Another communication challenge emerged from the connotations and inaccuracies surrounding the word "life", which impaired constructive debates, thus leading to misconceptions about the abilities of scientists to engineer or even create living organisms. Finally, it appeared that synthetic biologists tend to overestimate the knowledge of non-biologists, further affecting communication. The motivation and ability of synthetic biologists to communicate their work outside their research field needs to be fostered, notably towards policymakers who need a more accurate and technical understanding of the field to make informed decisions. Interdisciplinary events gathering scholars working in and around synthetic biology are an effective tool in addressing those issues.

synthetic biology↗
NASA NTRS2020

Corrosion Atmospheric Exposure Facility PRL #239 SWMU Assessment Report/Confirmation Sampling Work Plan

The National Aeronautics and Space Administration (NASA) Resource Conservation and Recovery Act (RCRA) permit requires identification and evaluation of known Solid Waste Management Units (SWMU) located at the Kennedy Space Center (KSC). The Corrosion Atmospheric Exposure Facility (CAEF), also known as facility number K8-0600, and the Corrosion Test Area (CTA); also known as facility number K8-0237, herein referred to as the site, is designated Potential Release Location (PRL) 239 under the NASA RCRA permit. A SWMU Assessment (SA) was conducted between November 2019 and February 2020 to identify potential environmental impacts related to current and historic operations being conducted at the site. The SA included a site reconnaissance visit in February 2020, interviews with various personnel possessing knowledge of past work practices and operations at the site, and review of available historical documentation, engineering drawings, and facility inspection reports. Current site conditions were documented in photographs. Soil types and wildlife habitat were also evaluated. The objective of the assessment was to identify potential locations of concern (LOC) at the site and to determine whether further evaluation is required.

Kimberly Clower↗
DOE OSTI2017

Examples of Use of SINBAD Database for Nuclear Data and Code Validation

Benchmark experiments can serve several purposes and the availability of suitable experimental data is fundamental to ensure that modelling tools meet the requirements of nuclear industry and licensing needs. Essentially, they are used for: - validation of nuclear cross-section data, - validation of nuclear codes and models used, - qualification and training of users through benchmarking and code comparison exercises. The Shielding Integral Benchmark Archive and Database (SINBAD) project was started in the early 1990's at the OECD Nuclear Energy Agency Data Bank (NEA DB) and the Radiation Safety Information Computational Center (RSICC) as a collection of quality experiments for validating and benchmarking computer codes and data for radiation transport and shielding applications. Currently, the SINBAD database comprises over 100 benchmark compilations and evaluations of relevance to: - reactor shielding, pressure vessel dosimetry (48); - fusion blanket neutronics (31); - accelerator shielding (23). In order to facilitate their use, the data are organized in the standardized format structure. The index and the master document (called abstract) use the Hyper Text Markup Language (HTML) format with links to text files, figures, Portable Document Format (pdf) documents and computer code inputs. The format allows easy access and forward/backward navigation among the data and has proved to be suitable, general enough and above all easy (and low-cost) to maintain. In addition to the characterization of the radiation source, description of the shielding set-up, the instrumentation and the relevant detector measurements, most sets in SINBAD contain also the deterministic or Monte Carlo radiation transport computer model used for the interpretation of the experiment and, where available, results from uncertainty analysis. The set of primary documents used for the benchmark compilation and evaluation are provided in computer readable form. The database is intended for different types of users, including nuclear data evaluators, computer code developers, experiment designers and university students. SINBAD is available from the NEA Data Bank and RSICC (see https://www.oecdnea.org/science/wprs/shielding/sinbad/). Up to now several hundreds of SINBAD packages were distributed from the NEA DB and RSICC. Since 2011 the maintenance and further development of the database is coordinated in the scope of the OECD NEA Nuclear Science Committee (NSC) Working Party on Scientific Issues of Reactor Systems (WPRS) Expert Group on Radiation Transport and Shielding (EGRTS). A key objective of the group is to identify, evaluate and preserve experimental data on shielding benchmarks. The Expert Group maintains close links with the International Reactor Physics Experiment Evaluation (IRPhE) and International Criticality Safety Benchmark Evaluation (ICSBEP) projects, as well as in co-ordination with the JEFF and EFF NEA Data Bank projects and with the SATIF community of accelerator shielding specialists. In the last years, much effort was devoted to the quality review of the available benchmark information.

42 ENGINEERING↗